A divided Supreme Court said Thursday that police and courts must consider a child's age when examining whether a boy or girl is in custody, a move the court's liberals called "common sense" but the conservatives called an "extreme makeover" of Miranda rights.

The 5-4 decision came in a case in which police obtained a confession from a seventh-grade special education student while questioning him at school about a rash of break-ins in Chapel Hill, N.C., without reading him his Miranda rights, telling him he could leave or call his relatives.

Justice Sonia Sotomayor, a former prosecutor who wrote the opinion, said police have to consider the child's age before talking to him or her about a crime. Courts also have to take the child's age into consideration when deciding whether that confession can be used in court, she said.

"It is beyond dispute that children will often feel bound to submit to police questioning when an adult in the same circumstances would feel free to leave," Sotomayor said, adding there was no reason for "police officers or courts to blind themselves to that commonsense reality."

But Justice Samuel Alito, also a former prosecutor, said the point of Miranda was that police would have clear, objective guidelines to follow. Opening the door to considering age likely will mean that other characteristics could soon be added to the list, such as educational level, I.Q. and cultural background, he said.

"Safeguarding the constitutional rights of minors does not require the extreme makeover of Miranda that today's decision may portend," Alito said in the dissent.

The special education student, known as JDB in court papers, was 13 in 2005 when he confessed while interviewed by police and school officials in a closed room at his school.